“He is the most important man in the world of sports . . . It is a sad day.”MSG PRESIDENT DAVE CHECKETTSThe days ahead could be the darkest in the history of the National Basketball Association. And the league must traverse the path without its brightest star, Michael Jordan.

“It is a major, major blow for the league,” said Madison Square Garden President Dave Checketts. “He is the most important man in the world of sports, a man who is recognized internationally. It is a sad day.”

Jordan, 35, is expected to hang up his commercially endorsed athletic shoes for the second time in five years today when he makes the announcement in Chicago’s United Center.

It’s an announcement that brings sorrow to the hearts of most league executives, but joy to any team that would be a pretender to the throne.

For six of the past eight seasons, Jordan held a steel stranglehold on the NBA championship trophy, lending it out twice while he played baseball.

And now he walks away at a time when the league may need him most.

For six months, the NBA and its players waged the ugliest labor war in its history. At the feel-good press conference after announcing ratification of a new deal last week, talk was of the work ahead, of winning back the fans.

But the one man who could win back so many fans with a quick flick of his jump-shooting wrist, with a juke of his soaring hips, with a wag of his tongue is gone.

“The NBA and the fans and America and society and history [are] losing the greatest influence that sports has ever had,” said Miami Heat coach Pat Riley, whose time in New York produced Knicks-Bulls games that were some of the most spirited, physical, memorable events in NBA history.

“The true meaning of leadership is one’s performance, nothing more, nothing less. He has influenced the world. He has influenced me. He has influenced teammates. That’s where his legacy is. His legacy is he’s had the most influence of any … athlete in the history of any sport.”

It is not something you replace. In American sports history, perhaps three men have truly transcended sport: Babe Ruth, Muhammad Ali and Jordan. Jordan’s departure is a staggering setback for the league.

“There is no replacement,” said ex-Detroit Piston player Joe Dumars, whose defense was the model on how to play Jordan. “You hear people say someone will fill his shoes. I don’t see it. He is the exception to the rule.”

NBA Commissioner David Stern and other league executives declined comment yesterday, waiting until after Jordan makes it official.

Jordan’s accomplishments beyond six title rings and five Most Valuable Player trophies? They would fill a book to rival Manhattan’s Yellow Pages.

You could start with 10 scoring titles in 13 seasons since he left his beloved North Carolina (where he won an NCAA title, of course). His 31.5-point scoring average is the highest in league history. And in 1995-96 he became only the second man in league history to take the MVP trophy in the playoffs, regular season and All-Star Game in the same season.

The first to do it was Willis Reed with the Knicks in 1969-70.

“The best,” Reed said emphatically. “There were arguments between myself and [former teammate] Johnny Green when we used to talk about who was the best, whether it was Oscar Robertson or Elgin Baylor. I always thought Oscar because of all the things he did. Johnny thought Elgin because he had to guard him. But after watching Michael all these years from college all the way through 13 years of pro basketball he’s the best. Without a doubt.”

All of that is from an athletic standpoint. Somehow, some way the game will survive.

“There always was an NBA before Michael Jordan and there will always be an NBA after Michael Jordan. But I don’t think in your lifetime there’ll be another player like Michael Jordan,” said free agent Derrick Coleman.

“Someone will take the mantle. They said it [was a disaster] when [Bob] Cousy left. They said it when [Bill] Russell left. They said it when Magic [Johnson] and [Larry] Bird left: ‘It’ll never be the same.’ Now they’re saying it with Michael,” allowed Nets coach John Calipari.

“But someone will take the banner. There are enough good players who are terrific guys in this league to do it. I just hope they’ve learned that it wasn’t about ‘Showtime for Michael.’ It was about winning a championship.”

Jordan was the third pick in the 1984 draft – behind Hakeem Olajuwon and Sam Bowie – after his run with the Tarheels. He retired for the first time in October 1993 following the murder of his father. He said he had done all he wanted to do in basketball and hoped to try his skills at baseball. As an outfielder in the White Sox farm system, he proved he was a helluva shooting guard.

“I think everybody knew that was a respite, a respite based on a tragedy in his life, also an illusion and desire to take a year off,” Riley said.

Jordan dominance was so overwhelming in every aspect. Statistically, he has no equal. Financially, his impact was estimated by Fortune magazine recently at $10 billion.

“He’s a big part of the reason guys are able to make $20 million,” said Knicks guard Allan Houston. “So he should be able to do anything he wants to do at this time.”

One thing Jordan’s departure does is balance the competitive landscape of the NBA. Some embraced the notion, some waved it off.

“If you are one of those three or four teams that truly felt you have a chance to win it, you can lie and say what you want, but you’re doing back flips,” said Calipari, who praised Jordan’s genuine appeal as a person and downright infectious personality.

Checketts said any rejoicing over Jordan’s departure is “terribly short-sighted” because of the impact he has had on the sport.

“This is absolutely the worst time for him to leave because he is so good for basketball,” said Nets center Rony Seikaly.